| 摘要 |
1,229,065. Cooling rings. MITSUBISHI PETROCHEMICAL CO. Ltd. 3 April, 1969 [6 April, 1968; 26 April, 1968; 17 May, 1968], No. 17733/69. Heading B5B. A ring for cooling tubular thermoplastic films after extrusion is shown in Figs. 1 and 3. Fig. 3 shows the mode of action of the ring. A tubulr film f is produced by melt extrusion from the slit b of the circular die a, and is inflated by reducing the external pressure on the film. The cooling medium, e.g. air, is supplied to the ring and ejected through the annular slits 35 and 37. In order to stabilize the film in the region of the cooling slits, the slits 25 and 39 in the hollow annular chambers shown are provided. The cooling medium is supplied via the conduit 2 and enters the cooling ring via the aperture 3. From the chamber 33 the cooling medium reached the slit 35, via the aperture 15, and tortuous chamber 34. Similarly the cooling medium reaches the slit 37 via a tortuous passage 36. The primary cooling slit 35 is inclined to the vertical at an angle between 30 to 60 degrees and the secondary cooling slit is inclined to the vertical at an angle between 0 to 30 degrees. The widths of the slits 35 and 37 together with the apertures of the stabilizing chambers 25 and 39 may be adjusted by means of the threadably mounted members 7, 8 and 9. A number of variations are given in the Specification including a cooling ring (Fig. 7, not shown) in which the slits are rotatable about the axis of the ring. |
